The abrupt move shocked many when it was announced early Monday, leaving investors and analysts wondering why Chênevert would choose to leave the company at this time and with so little notice.

Following an established succession plan, UTC's board tapped Gregory J. Hayes, its chief financial officer, to replace Chênevert as president, chief executive and director. The board both accepted Chênevert's retirement and named Hayes on Sunday.

The character of Chênevert's departure breaks from what seems to be a United Technologies tradition of carefully choreographed successions. And past chief executives also have largely come from the operations side of the business, not finance like Hayes.

United Technologies explains the move simply as Chênevert's retirement and would not elaborate. Analysts, however, speculated there was more to the succession than that, possibly personal reasons or a disagreement about the company's strategic direction.

Courtesy of UTC

Gregory J. Hayes has replaced Louis R. Chênevert as CEO of United Technologies.

Gregory J. Hayes has replaced Louis R. Chênevert as CEO of United Technologies. (Courtesy of UTC)

"This is an unpleasant and unplanned exit, there's no doubt about that. And the board is doing as well as they can to navigate their way through it," said Jeffrey Sonnenfeld, senior associate dean at Yale School of Management and the author of "The Hero's Farewell: What Happens When CEOs Retire."

"It's pretty antiseptic, cold, crisp," he said.

During the six years Chênevert led the Hartford-based conglomerate, he focused the company on its aerospace and building systems by selling divisions that manufactured wind turbines, fuel cells and rocket engines. The company remains the largest private employer in Connecticut.

Chênevert, 57, took the company through a major acquisition of Goodrich Corp. for $16.5 billion in 2012.

Last February, Chênevert wrapped up a deal with Connecticut to break ground on capital projects across the state and to keep certain divisions of the company where they are for a number of years in exchange for as much as $400 million in tax breaks.

Before becoming chief executive, Chênevert was the company's chief operating officer for two years and the president of Pratt & Whitney before that.

Hayes takes over at a critical time for United Technologies.

Its stock has underperformed in the past year. Executives, Hayes and Chênevert included, have promised steep growth from a thick backlog of aerospace sales. And its rollout of new products, including the engine for the Joint Strike Fighter and the PurePower commercial aircraft engine, has been bumpy.

Hayes, 54, has been the company's chief financial officer for the past six years. Four years ago, he took serious heat in Connecticut for comments made to Wall Street analysts about the cost of doing business in the state.

"Anyplace outside of Connecticut is low-cost," Hayes said in March 2010, paraphrasing a comment from another United Technologies executive. The comment rang stingingly clear as UTC shrank its workforce in recent years. To some, the recent deal for tax breaks with the Malloy administration was proof that the cuts would be stemmed.

"United Technologies is an exceptional company with an impressive history of providing innovative products and services while also delivering strong shareowner returns," he said in a statement. "As a corporation, our No. 1 objective will continue to be satisfying our customers and meeting our financial commitments to shareowners."

The pledge to shareholders comes as United Technologies' stock has lagged. The company's shares are down just over 1 percent in the past year, while the S&P 500 has jumped nearly 15 percent and the aerospace and defense portion of the S&P 500 has increased nearly 12 percent.

John Moran, UTC spokesman, disagreed that the company's performance played into Chênevert's departure.

"This retirement is entirely unrelated to the financial performance of UTC," he said. "The board has a succession plan for just these reasons. The succession plan has been in place for several years so this should be a seamless transition."

If it's not related to financial performance, J.P. Morgan analyst Joseph Nadol sees two possibilities. One could be personal circumstances preventing Chênevert from continuing. The other is that he left because of a strategic disagreement with the board.

"One possible area of disagreement could be whether to keep the company's building systems and aerospace units together or to break them up," Nadol said. "Chênevert preferred to hold the company together, and his resignation could be a sign that the board will pursue a split."

Peter Arment, an analyst who covers the company for Sterne Agee, said the succession is a major surprise. "We don't know the reasons why," he said. "There wasn't any heads up that there was going to be a leadership change."

Shares of United Technologies fell 1.37 percent on the New York Stock Exchange on Monday, closing at $108.79 a share.

Sam Pearlstein, an analyst for Wells Fargo, said the sudden resignation could prove to be negative for the stock but not for long. "We do believe investors have a very positive view of Greg Hayes and that could lead to an improvement for the stock," he said.

The board replaced Chênevert's position as chairman with Edward A. Kangas, the former chairman and chief executive of Deloitte, Touche, Tohmatsu, and a member of the UTC board since 2008.

"The appointment of Greg Hayes to succeed Louis Chênevert continues the excellent leadership UTC has enjoyed for the past half century," Kangas said. "Greg is highly regarded by the board and by UTC employees, customers and shareowners. We are confident Greg will lead UTC to increasing profitability and shareowner returns."

Hayes, who the company said was elected Sunday, became part of United Technologies in the 1999 merger with Sundstrand Corp., where he was vice president of finance for Sundstrand Aerospace. He was named UTC vice president and controller in 2003, and vice president of accounting and controls in 2004. He was also put in charge of investor relations in 2006, and was named senior vice president and chief financial officer in 2008.

Hayes graduated from Purdue University in 1982 with a bachelor's degree in economics.